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6. As in step 4, the stored signal record is correlation processed and then added to any correlation
data previously processed and residing in the signal portion of the correlation memory.
7. As the signal and reference acquisitions are repeated, the peak correlation values in the correlation
record increase and would ultimately overflow the 12bit word size. To prevent this overflow
condition, the correlation process is terminated for either the signal or reference records when a
peak signal within the record exceeds a preset maximum value slightly under overflow. Once both
the reference and signal records have reached their maximum values or that maximum acquisition
count has been exceeded the acquisition process is terminated.
8. After the signal acquisition process is complete, a lowpass and DC restoring filtering process
typically cleansup the waveform to improve the final measurement accuracy at low signal
conditions and short range. This function can be disabled by resetting the filter enable bit in control
register 4 for improved accuracy and resolution at longer ranges.
Correlation Record
Distance measurements are based on the storage and processing of reference and signal correlation
records.
The figure below shows a correlation record for a sensor without optics at short distances of 0, 4 and 8 feet.
The reference record runs from 063 and the signal record from 64 to 130. Each sample point represents
2nsec or roughly one foot.
LIDARLite v1 "Silver Label" Manual , Updated: 08/13/15
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